CHARLES AUGUSTUS [Karl August] (1757-1828), grand-duke of Saxe-Weimar, son of Constantine, duke of Saxe-Weimar-Eisenach, and Anna Amalia of Brunswick, was born on the 3rd of September 1757. His father died when he was only nine months old, and the boy was brought up under the regency and supervision of his mother, a woman of enlightened but masterful temperament. His governor was Count Eustach von Görz, a German nobleman of the old strait-laced school; but a more humane element was introduced into his training when, in 1771, Wieland was appointed his tutor. In 1774 the poet Karl Ludwig von Knebel came to Weimar as tutor to the young Prince Constantine; and in the same year the two princes set out, with Count Görz and Knebel, for Paris. At Frankfort, Knebel introduced Karl August to the young Goethe: the beginning of a momentous friendship. In 1775 Karl August returned to Weimar, and the same year came of age and married Princess Louise of Hesse-Darmstadt.

One of the first acts of the young grand-duke was to summon Goethe to Weimar, and in 1776 he was made a member of the privy council. “People of discernment,” he said, “congratulate me on possessing this man. His intellect, his genius is known. It makes no difference if the world is offended because I have made Dr Goethe a member of my most important collegium without his having passed through the stages of minor official professor and councillor of state.” To the undiscerning, the beneficial effect of this appointment was not at once apparent. With Goethe the “storm and stress” spirit descended upon Weimar, and the stiff traditions of the little court dissolved in a riot of youthful exuberance. The duke was a deep drinker, but also a good sportsman; and the revels of the court were alternated with break-neck rides across country, ending in nights spent round the camp fire under the stars. Karl August, however, had more serious tastes. He was interested in literature, in art, in science; critics, unsuspected of flattery, praised his judgment in painting; biologists found in him an expert in anatomy. Nor did he neglect the government of his little state. His reforms were the outcome of something more than the spirit of the “enlightened despots” of the 18th century; for from the first he had realized that the powers of the prince to play “earthly providence” were strictly limited. His aim, then, was to educate his people to work out their own political and social salvation, the object of education being in his view, as he explained later to the dismay of Metternich and his school, to help men to “independence of judgment.” To this end Herder was summoned to Weimar to reform the educational system; and it is little wonder that, under a patron so enlightened, the university of Jena attained the zenith of its fame, and Weimar became the intellectual centre of Germany.

Meanwhile, in the affairs of Germany and of Europe the character of Karl August gave him an influence out of all proportion to his position as a sovereign prince. He had early faced the problem presented by the decay of the Empire, and began to work for the unity of Germany. The plans of the emperor Joseph II., which threatened to absorb a great part of Germany into the heterogeneous Habsburg monarchy, threw him into the arms of Prussia, and he was the prime mover in the establishment of the league of princes (Fürstenbund) in 1785, by which, under the leadership of Frederick the Great, Joseph's intrigues were frustrated. He was, however, under no illusion as to the power of Austria, and he wisely refused the offer of the Hungarian crown, made to him in 1787 by Prussia at the instance of the Magyar malcontents, with the dry remark that he had no desire to be another “Winter King.” In 1788 Karl August took service in the Prussian army as major-general in active command of a regiment. As such he was present, with Goethe, at the cannonade of Valmy in 1792, and in 1794 at the siege of Mainz and the battles of Pirmasenz (September 14) and Kaiserslautern (October 28-30). After this, dissatisfied with the attitude of the powers, he resigned; but rejoined on the accession of his friend King Frederick William III. to the Prussian throne. The disastrous campaign of Jena (1806) followed; on the 14th of October, the day after the battle, Weimar was sacked; and Karl August, to prevent the confiscation of his territories, was forced to join the Confederation of the Rhine. From this time till after the Moscow campaign of 1812 his contingent fought under the French flag in all Napoleon's wars. In 1813, however, he joined the Grand Alliance, and at the beginning of 1814 took the command of a corps of 30,000 men operating in the Netherlands.

At the congress of Vienna Karl August was present in person, and protested vainly against the narrow policy of the powers in confining their debates to the “rights of the princes” to the exclusion of the “rights of the people.” His services in the war of liberation were rewarded with an extension of territory and the title of grand-duke; but his liberal attitude had already made him suspect, and his subsequent action brought him still further into antagonism to the reactionary powers. He was the first of the German princes to grant a liberal constitution to his state under Article XIII. of the Act of Confederation (May 5, 1816); and his concession of full liberty to the press made Weimar for a while the focus of journalistic agitation against the existing order. Metternich dubbed him contemptuously “der grosse Bursche” for his patronage of the “revolutionary” Burschenschaften; and the celebrated “festival” held at the Wartburg by his permission in 1818, though in effect the mildest of political demonstrations, brought down upon him the wrath of the great powers. Karl August, against his better judgment, was compelled to yield to the remonstrances of Prussia, Austria and Russia; the liberty of the press was again restricted in the grand-duchy, but, thanks to the good understanding between the grand-duke and his people, the régime of the Carlsbad Decrees pressed less heavily upon Weimar than upon other German states.

Karl August died on the 14th of June 1828. Upon his contemporaries of the most various types his personality made a great impression. Karl von Dalberg, the prince-primate, who owed the coadjutorship of Mainz to the duke's friendship, said that he had never met a prince “with so much understanding, character, frankness and true-heartedness”; the Milanese, when he visited their city, called him the “uomo principe”; and Goethe himself said of him “he had the gift of discriminating intellects and characters and setting each one in his place. He was inspired by the noblest good-will, the purest humanity, and with his whole soul desired only what was best. There was in him something of the divine. He would gladly have wrought the happiness of all mankind. And finally, he was greater than his surroundings. . . . Everywhere he himself saw and judged, and in all circumstances his surest foundation was in himself.” He left two sons: Charles Frederick (d. 1853), by whom he was succeeded, and Bernhard, duke of Saxe-Weimar (1792-1862), a distinguished soldier, who, after the congress of Vienna, became colonel of a regiment in the service of the king of the Netherlands, distinguished himself as commander of the Dutch troops in the Belgian campaign of 1830, and from 1847 to 1850 held the command of the forces in the Dutch East Indies. Bernhard's son, William Augustus Edward, known as Prince Edward of Saxe-Weimar (1823-1902), entered the British army, served with much distinction in the Crimean War, and became colonel of the 1st Life Guards and a field marshal; in 1851 he contracted a morganatic marriage with Lady Augusta Gordon-Lennox (d. 1904), daughter of the 5th duke of Richmond and Gordon, who in Germany received the title of countess of Dornburg, but was granted the rank of princess in Great Britain by royal decree in 1866. Karl August's only daughter, Caroline, married Frederick Louis, hereditary grand-duke of Mecklenburg-Schwerin, and was the mother of Helene (1814-1858), wife of Ferdinand, duke of Orleans, eldest son of King Louis Philippe.

Karl August's correspondence with Goethe was published in 2 vols. at Weimar in 1863. See the biography by von Wegele in the Allgem.deutsche Biographie.